Mazda MX-6 1998, Workshop Manual

Page: 219 / 1282

TROUBLESHOOTING [ENGINE CONTROL KL]
STEP
INSPECTION
ACTION
10 CHECK MAF SIGNAL CIRCUIT OUTPUT
• Key off.
• MAF sensor connected.
• Breakout box Installed, PCM connected.
• Key on, engine running.
Note
• If stabilized idle is not stabilized at
minimum of 700 rpm, go to ENGINE
SYMPTOM TROUBLESHOOTING.
• Measure voltage between Test Pin 88 at
breakout box and battery negative post.
• Is voltage at idle between 0.34 and 1.96
volts?
Yes
MAF signal circuit to PCM is okay.
Go to next step.
No MAF signal circuit or ground circuit is open in MAF sensor,
or MAF signal circuit is shorted to PCM ground circuit in
MAF sensor.
REPLACE MAF sensor.
REMOVE breakout box.
RECONNECT PCM.
RESET PCM to completely clear DTCs.
c r After Repair Procedure
COMPLETE OBD II Drive Mode.
RERUN OBD Test.
11 VERIFY MAF SIGNAL CIRCUIT INPUT AND
OUTPUT
• Key off.
• MAF sensor connected.
• Breakout box installed, PCM connected.
• Key on, engine running.
• Measure voltage between Test Pin 88 and
Test Pin 36 at breakout box.
• Is voltage between 0.34 and 1.96 volts?
Yes PCM ground circuit in MAF sensor is okay.
Go to next step.
No PCM ground circuit open in MAF sensor.
REPLACE MAF sensor.
REMOVE breakout box.
RECONNECT PCM.
RESET PCM to completely clear DTCs.
c r After Repair Procedure
COMPLETE OBD II Drive Mode.
RERUN OBD Test.
12 CHECK MAF SIGNAL CIRCUIT OUTPUT
WITH NGS TESTER
• Key off.
• MAF sensor connected.
• Breakout box Installed, PCM connected.
• Key on, engine running.
• Access MAF PID with NGS tester at idle.
•
Is MAF PID within specified value?
e r 01-40B MASS AIR FLOW SENSOR
INSPECTION [KL],
Yes Unable to identify fault at this time.
Check possible intermittent.
Go to ENGINE SYMPTOM TROUBLESHOOTING No.27
No MAF signal circuit or PCM ground circuit is open or
shorted together in PCM.
REPLACE PCM.
REMOVE breakout box.
RECONNECT PCM.
RESET PCM to completely clear DTCs.
f t
After Repair Procedure
COMPLETE OBD II Drive Mode.
RERUN OBD Test.
13
CHECK MAF SENSOR OUTPUT VOLTAGE
Note
• DTC P1101 could be generated by low
charged vehicle battery or garage exhaust
ventilation system. Service battery as
necessary. Then remove ventilation system
and properly vent to outside atmosphere.
Return key on engine off (KOEO) Self-Test.
• Key off.
• Check that MAF sensor in corrected. If not,
service as necessary.
• Disconnect PCM. Inspect for damaged or
pushed out pins, corrosion, loose wires,
etc. Service as necessary.
• NGS tester connected.
• Install breakout box, connect PCM to
breakout box.
• Key on, engine off.
• Measure between Test Pin 88 and Test
Pins 24 or 103 at breakout box.
• Is voltage greater than 0.20 volts?
Yes MAF signal voltage is greater than expected.
Go to step 7.
No Go to step 3.
01-01B-13